Advertisement Upon Join

I’m wondering how I would go about having an advertisement upon join on my server. Since we have to download player models through steam workshop now I would like for people to know right when they join with like a pop up message or something that they have to download my addon pack in order to see models on my server. How would I do this?

I would just recomend using a GMA extractor, then getting a resource generator, then apply them to FastDL, thats what i’ve done with a couple of the custom models from the workshop.